Chapter 1 of 16

Tamil Nadu (TNBSE)Class 6 Mathematics★ 6-10 marks in the TN Class 6 Term 1 exam through place value, ordering, rounding and BODMAS sums

Numbers (Term 1) - Whole Numbers

Samacheer Kalvi (TN State Board) Class 6 Maths — Term 1 Chapter 1, Numbers. Reading and writing large numbers, place value and the Indian and international systems, ascending and descending order, rounding (estimation), the properties of whole numbers and the BODMAS rule, with worked examples, exercises and quick revision.

⏱ 15 min readEasy difficulty✓ Free · NCERT-aligned

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Key points, glossary and the questions most likely to show up.

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By the end of this chapter you'll be able to…

1Read and write large numbers with place value
2Use the Indian and international systems
3Arrange numbers in ascending and descending order
4Round numbers to a given place
5Apply the BODMAS rule

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Why this chapter matters

Reading large numbers, place value and BODMAS are the foundation of all arithmetic. These are directly and frequently tested in the TN Class 6 Term 1 exam.

Before you start — revise these

A 5-minute refresher here will save you 30 minutes of confusion below.

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Class 5 — Large Numbers

Place value basics.

Numbers (Whole Numbers) — Class 6 Maths (Samacheer Kalvi)

TN State Board (Samacheer Kalvi) Class 6 Mathematics, Term 1 — Chapter 1. Large numbers, place value, ordering, rounding and BODMAS.

1. About this chapter

This chapter covers large numbers and place value, ascending and descending order, rounding (estimation), the properties of whole numbers, and the BODMAS rule.

2. Place value and number systems

Whole numbers are 0, 1, 2, 3 … (natural numbers together with 0).
Place value tells the value of a digit by its position. In the Indian system the periods are ones, thousands, lakhs, crores; in the international system they are ones, thousands, millions.
Example: in 5,47,308 the digit 4 is in the ten-thousands place → value 40,000.

3. Ordering and rounding

Ascending order = smallest to largest; descending order = largest to smallest. Compare by the number of digits first, then place by place.
Rounding (estimation): to round to a given place, look at the next digit — 5 or more rounds up, less than 5 rounds down. Example: 4,627 rounded to the nearest hundred → 4,600.

4. Properties of whole numbers and BODMAS

Closure, commutative, associative hold for addition and multiplication; 0 is the additive identity and 1 the multiplicative identity; multiplication is distributive over addition.
BODMAS gives the order of operations: Brackets, Orders (powers), Division, Multiplication, Addition, Subtraction.

5. Worked examples

Example 1. Write the place value of 7 in 3,78,945. 7 is in the ten-thousands place → 70,000.

Example 2. Round 58,372 to the nearest thousand. Next digit 3 < 5 → 58,000.

Example 3. Simplify 12 + 6 × (8 − 3) using BODMAS. Brackets: 8 − 3 = 5 → 6 × 5 = 30 → 12 + 30 = 42.

6. Exercises (Samacheer Kalvi)

Write 9,80,452 in words (Indian system).
Write the place value of each digit in 7,06,219.
Arrange in ascending order: 45,231; 4,532; 54,123; 5,423.
Round 7,649 to (a) the nearest ten (b) the nearest hundred.
Simplify using BODMAS: (a) 20 − 4 × 3 (b) (15 + 5) ÷ 4.

7. Common mistakes

Mistake: Adding before multiplying. Fix: Follow BODMAS — multiply/divide before add/subtract.
Mistake: Rounding the wrong way at 5. Fix: A next digit of 5 or more rounds up.
Mistake: Confusing place value with face value. Fix: Place value depends on position; face value is the digit itself.

8. Quick revision

Term 1 · Ch 1 · whole numbers.
Place value by position (Indian: ones/thousands/lakhs/crores).
Ascending = small→large; descending = large→small.
Rounding: next digit ≥ 5 rounds up. BODMAS = Brackets, Orders, Division, Multiplication, Addition, Subtraction.

Key formulas & results

Everything you need to memorise, in one card. Screenshot this for revision.

Place value

digit × value of its position

Indian: ones, thousands, lakhs, crores.

Rounding

next digit ≥ 5 round up, < 5 round down

Estimation.

BODMAS

Brackets, Orders, Division, Multiplication, Addition, Subtraction

Order of operations.

Properties

commutative, associative, distributive; identities 0 and 1

For + and ×.

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Common mistakes & fixes

These are the exact errors that cost students marks in board exams. Read them once, save yourself the trouble.

WATCH OUT

✗ Adding before multiplying

✓ Follow BODMAS — multiply/divide before add/subtract.

WATCH OUT

✗ Rounding the wrong way at 5

✓ A next digit of 5 or more rounds up.

WATCH OUT

✗ Confusing place value with face value

✓ Place value depends on position; face value is the digit itself.

NCERT exercises (with solutions)

Every NCERT exercise from this chapter — what it covers and how many questions to expect.

Place value and number names

Write numbers in words and find place values.

Questions

Ordering and rounding

Arrange and round numbers.

Questions

BODMAS

Simplify using the order of operations.

Questions

Practice problems

Try each one yourself before tapping "Show solution". Active recall > rereading.

Q1EASY· Place value

Write the place value of 7 in 3,78,945.

▶ Show solution

70,000 (ten-thousands place).

Q2EASY· Rounding

Round 58,372 to the nearest thousand.

▶ Show solution

58,000.

Q3EASY· Ordering

Arrange in ascending order: 45,231; 4,532; 54,123; 5,423.

▶ Show solution

4,532 < 5,423 < 45,231 < 54,123.

Q4MEDIUM· BODMAS

Simplify 12 + 6 × (8 − 3).

▶ Show solution

8 − 3 = 5; 6 × 5 = 30; 12 + 30 = 42.

Q5EASY· BODMAS

Simplify 20 − 4 × 3.

▶ Show solution

20 − 12 = 8.

Q6EASY· Number name

Write 9,80,452 in words (Indian system).

▶ Show solution

Nine lakh eighty thousand four hundred fifty-two.

5-minute revision

The whole chapter, distilled. Read this the night before the exam.

•Term 1 Chapter 1 of Samacheer Kalvi Class 6 Maths.
•Whole numbers are 0, 1, 2, 3, …; place value depends on position.
•Indian system: ones, thousands, lakhs, crores; international: ones, thousands, millions.
•Ascending = smallest to largest; descending = largest to smallest.
•Rounding: next digit 5 or more rounds up, less than 5 rounds down.
•BODMAS = Brackets, Orders, Division, Multiplication, Addition, Subtraction.

Tamil Nadu (TNBSE) marks blueprint

Where the marks come from in this chapter — so you can plan your prep.

Typical chapter weightage: 6-10 marks across place value, ordering, rounding and BODMAS

Question type	Marks each	Typical count	What it tests
Objective	1	3-5	Place value, rounding
Ordering	2	1	Ascending/descending
BODMAS	2	1-2	Order of operations

Prep strategy

Use a place-value chart for large numbers
Compare digit count first when ordering
Apply the 5-or-more rounding rule
Work through BODMAS step by step

Where this shows up in the real world

This chapter isn't just an exam topic — it lives in the world around you.

Money

Reading large amounts uses place value.

Estimation

Rounding gives quick approximate answers.

Calculations

BODMAS ensures correct multi-step results.

Exam strategy

Battle-tested tips from teachers and toppers for this chapter.

Write a place-value chart for big numbers
Order by digit count, then place by place
State the rounding rule used
Show each BODMAS step

Going beyond the textbook

For olympiad aspirants and curious learners — topics that build on this chapter.

Form the largest and smallest 6-digit numbers using 0, 3, 5, 7, 8, 9.
Simplify 100 − [20 + {6 × (3 + 2)}] using BODMAS.

Where else this chapter is tested

CBSE board isn't the only one — other exams test this chapter too.

TN Class 6 Term 1 ExamHigh

NMMS / Foundation MathsMedium

School unit testsHigh

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Questions students ask

The real ones — pulled from the Q&A community and tutor sessions.

Face value is the digit itself, while place value is the digit multiplied by the value of its position — for example, in 350 the face value of 5 is 5 but its place value is 50.

It gives one agreed order for doing operations so that everyone gets the same answer to an expression; without it, 2 + 3 × 4 could be read two different ways.

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